2017/09/30 by Mikel Berasaluce-González, Gabriele Honecker, Alexander Seifert
Physics and Astronomy · #hep-th #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2017.10.023
65 pages, 10 figures; v3: matches published version (ref + explanatory remarks added)
arxiv created 2017/11/14 · arxiv updated 2017/11/15
So-called `non-factorisable' toroidal orbifolds can be rewritten in a factorised form as a product of three two-tori by imposing an additional shift symmetry. This finding of Blaszczyk et al., arXiv:1111.5852, provides a new avenue to Conformal Field Theory methods, by which the vector-like massless matter spectrum - and thereby the type of gauge group enhancement on orientifold invariant fractional D6-branes - and the one-loop corrections to the gauge couplings in Type IIA orientifold theories can be computed in addition to the well-established chiral matter spectrum derived from topological intersection numbers among three-cycles. We demonstrate this framework for the ℤ4 × ΩR orientifolds on the A3 × A1 × B2-type torus. As observed before for factorisable backgrounds, also here the one-loop correction can drive the gauge groups to stronger coupling as demonstrated by means of a four-generation Pati-Salam example.